1. Field of the Invention
The present invention relates to a key switch, and more particularly, to a key switch with a keycap moving in an up and down manner to enhance air flow beneath the key switch.
2. Description of the Prior Art
With the development of very large scale integration (VLSI) complexity, the transistor""s operating frequency is increasing rapidly, causing high power consumption and a great amount of heat. The high temperature destroys the electrical device easily. In order to prolong life of the electrical device, heat dissipation is an important topic for researching. Because a portable computer is small and thin, ther heat generated by the electrical devices does not expel easily, therefore the heat dissipation is very important.
The heat dissipation method of an electrical device normally includes active and passive cooling methods. Active cooling utilizes a fan to take hot air away, but the operation of the fan for a long time consumes a large amount of electrical energy and makes noise. Passive cooling deceases the heat generated from the electrical device by redyucing the system efficiency. Neither of the two methods is good enough to dissipate the heat generated from the electrical decice.
Please refer to FIG. 1. FIG. 1 is a schematic diagram of a prior art personal computer 10 using another conventional heat dissipating method. The personal computer 10 incudes a housing 12, a keyboard 14, a processor 16, a chipset 18, and a heat conductive tube 20. The keyboard 14 covers a large part of the housing 12. The processor 16 and the chipset 18, are disposed under the keyboard 14, and generate a large amount of heat while operating. The heat conductive tube 20 is located under the the processor 16 and the chipset 18 for conducing the heat generated from the processor 16 and the chipset 18. Because the keyboard 14 occupies a great part of the housing 12, it is usually used for heat dissipation. The temperature of the area surrounding the procesor 16 and the chipset 18 is higher than the area far away them. Because the heat conductive tube 20 is made of metal and has a great conductivity, the heat can be conducted from the area with higher temperature to the area with lower temperatrue quickly for dissipating the heat. The heat conductive tube 20 can also use other heat dissipating devices that conduct the heat quickly, such as a metal heat sink. However, the efficiency of this method is not ideal for taking away the large amount of heat generated by the electrical decices, such as the processor 16 and the chipsety 18, and the active cooling is usually needed to dissipate the heat.
It is therefore a primary objective of the claimed invention to provide a key switch with a keycap moving in an up and down manner to enhance air flow beneath the key switch.
According to the claimed invention, a key switch of a computer keyboard comprises a keycap, an upper cover placed under the keycap, a lower cover placed under the upper cover, a connecting device connected between the keycap and the upper cover for moveably connecting the keycap above the upper cover in an up and down manner, and a heat dissipating device comprising a container and a piston. The top of the piston is fixed on the bottom of the keycap, the bottom of the piston is movably installed inside an opening formed on the top of the container, the bottom of the container is fixed on the lower cover, and a sidewall of the container comprises at least a first opening and at least a second opening formed between the upper cover and the lower cover for dissipating heat between the upper cover and the lower cover. When the keycap is depressed, the piston moves downward with the keycap so as to expel air inside the container through the first opening. When the keycap is released, the piston moves upward with the keycap allowing air outside the container to enter the container through the second opening.
It is an advantage of the claimed invention to use the key switch to move the air from a higher temperature area to a lower temperature area, dissipating heat without and requiring more power.
These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.